1. Field of the Invention
The present invention relates to a fiber plate (also called fiber optic plate), a radiation image pickup apparatus, a producing method therefor and a radiation image pickup system provided with the same, and more particularly to a fiber plate adapted for use in a radiation image pickup apparatus provided with conversion means for converting a radiation into light and a photoelectric converting element for converting light into an electrical signal and adapted to guide the light from the conversion means to the photoelectric converting element.
In the field of radiation image pickup apparatus, particularly of X-ray image pickup apparatus for medical purpose, there has been desired an X-ray image pickup apparatus of thin type, having a large image input area and capable of taking X-ray moving image with a high image quality. Also for the non-destructive testing apparatus for industrial use, there is required a thin and inexpensive X-ray image of a large area.
For such X-ray image pickup apparatus, there are proposed, for example, (1) an X-ray detecting apparatus having a fiber plate of which the fibers are inclined to prevent mutual interference of the non-light receiving areas of a CCD sensor thereby achieving a large area (as disclosed in the U.S. Pat. No. 5,563,414, and (2) an X-ray detecting apparatus having a fiber plate of which thickness is given a step difference to prevent mutual interference of the non-light receiving areas of a CCD sensor thereby achieving a large area (as disclosed in the U.S. Pat. No. 5,834,782).
FIG. 37 is a schematic cross-sectional view of an X-ray detecting apparatus of the above-mentioned configuration (1), composed of a phosphor 3 consisting for example of a scintillator for converting X-ray into visible light, individual fiber plates 2A consisting of optical fibers or the like for guiding the visible light, obtained by the phosphor 3, to an image pickup element 1, and an image pickup element 1A for converting the visible light, guided by the individual fiber plates 2A, into an electrical signal.
In this X-ray image pickup apparatus, the individual fiber plate 2A is inclined with respect to the image pickup element 1A, and, between the individual fiber plates 2A, there is provided a process circuit or the like for processing the electrical signal from each image pickup element 1A.
FIG. 38 is a schematic perspective view of an X-ray detecting apparatus of the above-mentioned configuration (2), wherein components equivalent to those in FIG. 37 are represented by corresponding numbers. As shown in FIG. 38, the length of the fiber plate 2 is partially changed and for example three image pickup elements are provided as a set with step differences therebetween, in order to provide each image pickup element with a process circuit.
However, in the above-described configuration (1), the light guide (entering/emerging) plane is inclined to the axis of the optical fiber, and the individual fiber plates are so arranged that the optical axes of the optical fibers mutually cross. It is difficult, with such configuration, to achieve compactization of the X-ray image pickup apparatus.
On the other hand, the above-described configuration (2) results in an increase in the dimension of the X-ray image pickup apparatus. Also as the alignment between each stepped portion and the image pickup element requires a high precision, the manufacturing process requires a large number of steps and also requires a highly precise aligning apparatus. In consideration of these facts, the configuration (2) is not practical.
Thus, the X-ray image pickup apparatuses of the conventional configurations have not been satisfactory in the increase in the size of the image pickup apparatus, in the cost reduction thereof and in the efficiency of the manufacturing process.
In consideration of the foregoing, an object of the present invention is to provide a large-area fiber plate suitable for compactization and cost reduction of the radiation image pickup apparatus and superior in the efficiency of the manufacturing process, and a radiation image pickup apparatus and a radiation image pickup system utilizing the same.
Another object of the present invention is to provide a method for producing a fiber plate and a radiation image pickup apparatus, capable of providing a large-area fiber plate, a radiation image pickup apparatus and a radiation image pickup system in inexpensive manner.
The present invention is featured in that, in a fiber plate in which plural individual fiber plates of a same thickness are so arranged in mutually adjacent manner as to provide a light guiding plane larger than that of an individual one fiber plate, each of the plural individual fiber plates is composed of a group of optical fibers having mutually parallel axes and the lateral faces of the plural individual fiber plates are so bonded that the axes of the optical fibers become mutually parallel.
In such invention, the axes of the optical fibers are preferably parallel or inclined to the normal line to the above-mentioned light guiding face. Also in such invention, at least either of the above-mentioned light guiding face or the above-mentioned lateral faces is preferably a polished surface.
Also in such invention, the above-mentioned lateral faces are preferably bonded by at least either of an adhesive or a metal.
Also in such invention, the portion of above-mentioned bonding is preferably a radiation intercepting bonded portion.
Also in such invention, the above-mentioned lateral faces preferably include a face crossing the normal line to the above-mentioned light guiding face.
The present invention is also featured in that, in a fiber plate in which plural individual fiber plates of a same thickness are so arranged in mutually adjacent manner as to provide a light guiding plane larger than that of an individual one fiber plate, each of the plural individual fiber plates is composed of a group of optical fibers having axes parallel to the normal line to the light guiding face, and the lateral faces of the plural individual fiber plates are so bonded that the axes of the optical fibers become mutually parallel, and the front face and the rear face constituting the light guiding faces of the fiber plate are same in area.
In such invention, the plural individual fiber plates are preferably bonded in the mutually parallel lateral faces thereof.
Also in such invention, the above-mentioned light guiding face is preferably a polished surface.
Also in such invention, the above-mentioned lateral face is preferably a polished face.
Also in such invention, the above-mentioned lateral faces are preferably bonded by at least either of an adhesive or a metal.
Also in such invention, the portion of above-mentioned bonding is preferably a radiation intercepting bonded portion.
Also in such invention, the above-mentioned lateral faces preferably include a face crossing the normal line to the above-mentioned light guiding face.
The present invention is further featured in that, in a radiation image pickup apparatus provided with a wavelength converting member for converting radiation into light, a photoelectric converting element for converting light into an electrical signal and a fiber plate positioned between the wavelength converting member and photoelectric converting element, the fiber plate are composed of plural individual fiber plates of a same thickness so arranged in mutually adjacent manner as to provide a light guiding plane larger than that of an individual one fiber plate, wherein each of the plural individual fiber plates is composed of a group of optical fibers having mutually parallel axes, and the lateral faces of the plural individual fiber plates are so bonded that the axes of the optical fibers become mutually parallel.
In such invention, the axes of the optical fibers are preferably parallel or inclined to the normal line to the above-mentioned light guiding face.
Also in such invention, at least either of the above-mentioned light guiding face or the above-mentioned lateral faces is preferably a polished surface.
Also in such invention, the above-mentioned lateral faces are preferably bonded by at least either of an adhesive or a metal.
Also in such invention, the portion of above-mentioned bonding is preferably a radiation intercepting bonded portion.
Also in such invention, the above-mentioned lateral faces preferably include a face crossing the normal line to the above-mentioned light guiding face.
Also in such invention, the width of the gap between the adjacent individual fiber plates is preferably smaller than the width of the pixel of the photoelectric converting element.
Also in such invention, it is preferable that the photoelectric converting element has plural pixels of mutually different light-receiving areas and that the width of the gap between the adjacent individual fiber plate is smaller than the width of a pixel having the smallest light-receiving area of the photoelectric converting element.
Also in such invention, the gap between the adjacent individual fiber plates is preferably positioned on the gap of chips constituting the photoelectric converting element.
Also in such invention, the gap between the adjacent individual fiber plates is preferably positioned on the effective pixel area of chips constituting the photoelectric converting element.
Also in such invention, the joint line formed by the gaps of the adjacent individual fiber plates crosses the joint line formed by the gaps of the chips constituting the photoelectric converting element with an angle larger than 0xc2x0 and smaller than 90xc2x0.
The present invention is further featured in that, in a radiation image pickup apparatus provided with a wavelength converting member for converting radiation into light, a photoelectric converting element for converting light into an electrical signal and a fiber plate positioned between the wavelength converting member and photoelectric converting element, the fiber plate are composed of plural individual fiber plates of a same thickness so arranged in mutually adjacent manner as to provide a light guiding plane larger than that of an individual one fiber plate, wherein each of the plural individual fiber plates is composed of a group of optical fibers having axes parallel to the normal line to the above-mentioned light guiding plane;
the lateral faces of the plural individual fiber plates are so bonded that the axes of the optical fibers become mutually parallel, and
the front surface and the rear surface constituting the light guiding planes of the fiber plate have a same area.
In such invention, the above-mentioned lateral faces are preferably polished faces.
Also in such invention, the above-mentioned light guiding faces are preferably polished faces.
Also in such invention, the above-mentioned lateral faces are mutually bonded by at least either of an adhesive or a metal.
Also in such invention, the portion of above-mentioned bonding is preferably a radiation intercepting bonded portion.
Also in such invention, the above-mentioned lateral faces preferably include a face crossing the normal line to the above-mentioned light guiding face.
Also in such invention, the width of the gap between the adjacent individual fiber plates is preferably smaller than the width of the pixel of the photoelectric converting element.
Also in such invention, it is preferable that the photoelectric converting element has plural pixels of mutually different light-receiving areas and that the width of the gap between the adjacent individual fiber plate is smaller than the width of a pixel having the smallest light-receiving area of the photoelectric converting element.
Also in such invention, the gap between the adjacent individual fiber plates is preferably positioned on the gap of chips constituting the photoelectric converting element.
Also in such invention, the gap between the adjacent individual fiber plates is preferably positioned on the effective pixel area of chips constituting the photoelectric converting element.
Also in such invention, the joint line formed by the gaps of the adjacent individual fiber plates crosses the joint line formed by the gaps of the chips constituting the photoelectric converting element with an angle larger than 0xc2x0 and smaller than 90xc2x0.
The present invention is further featured in that, in a radiation image pickup apparatus consisting of an array of a plurality of radiation image pickup units, each provided with a wavelength converting member for converting radiation into light, a photoelectric converting element chip for converting light into an electrical signal and a fiber plate positioned between the wavelength converting member and photoelectric converting element, the lateral faces of the plural individual fiber plates of the plural radiation image pickup units are so bonded that the axes of the optical fibers become mutually parallel.
In such invention, the above-mentioned lateral faces are preferably polished surfaces.
Also in such invention, the above-mentioned light guiding face is preferably a polished face.
Also in such invention, in the above-mentioned radiation image pickup unit, the wavelength converting member, the photoelectric converting element chip and the individual fiber plate have a substantially same size.
The present invention is further featured by a method for producing a fiber plate, comprising:
a step of preparing plural individual fiber plates of a same thickness, each consisting of a group of optical fibers having mutually parallel axes;
a step of arranging the plural individual fiber plates in such adjacent manner as to provide a light guiding face larger in area than the light guiding face of each individual one fiber plate; and
a step of so bonding the lateral faces of the plural individual fiber plates that the axes of the optical fibers become mutually parallel.
In such invention, the method preferably comprises:
a step of bonding at least two of the plural individual fiber plates thereby forming a set of individual fiber plates; and
a step of further bonding plural sets of the individual fiber plates thereby forming the above-mentioned fiber plate.
Also in such invention, it is preferable to polish lateral faces of the set of the individual fiber plates and then to bond the plural sets of the individual fiber plates in such a manner that the lateral faces are mutually adjacent.
Also in such invention, the lateral faces of the adjacent individual fiber plates are bonded with a metal or an adhesive.
Also in such invention, the surfaces of the plural individual fiber plates are preferably poslished after the fiber plates are bonded.
Also in such invention, the method preferably comprises:
a step of preparing plural individual fiber plates of a same thickness, each consisting of a group of optical fibers having axes parallel to the normal line to the light guiding face;
a step of arranging the plural individual fiber plates in such adjacent manner as to provide a light guiding face larger in area than the light guiding face of each individual one fiber plate; and
a step of so bonding the lateral faces of the plural individual fiber plates that the axes of the optical fibers become mutually parallel.
Also in such invention, the method preferably comprises:
a step of bonding at least two of the plural individual fiber plates thereby forming a set of individual fiber plates; and
a step of further bonding plural sets of the individual fiber plates thereby forming the above-mentioned fiber plate.
Also in such invention, it is preferable to polish lateral faces of the set of the individual fiber plates and then to bond the plural sets of the individual fiber plates in such a manner that the lateral faces are mutually adjacent.
Also in such invention, the lateral faces of the adjacent individual fiber plates are bonded with a metal or an adhesive.
Also in such invention, the surfaces of the plural individual fiber plates are preferably poslished after the fiber plates are bonded.
Also in such invention, the method preferably comprises:
a step of preparing plural individual fiber plates each consisting of a group of optical fibers having mutually parallel axes;
a step of arranging the plural individual fiber plates in such adjacent manner as to provide a light guiding face larger in area than the light guiding face of each individual one fiber plate; and
a step of bonding the lateral faces of the plural individual fiber plates and then polishing the surfaces of the fiber plates.
The present invention is further featured by a method for producing a radiation image pickup apparatus comprising:
a step of preparing the above-described fiber plate; and
a step of bonding to the photoelectric converting element.
In such invention, it is preferable, after the bonding of the fiber plate with planarized surfaces and the photoelectric converting element, to bond the sheet-shaped wavelength converting member to the fiber plate.
Also in such invention, it is preferable, after the bonding of the fiber plate with planarized surfaces and the sheet-shaped wavelength converting member, to bond the photoelectric converting element thereto.
The present invention is further featured by a radiation image pickup system comprising:
signal processing means for processing a signal from the above-mentioned radiation image pickup apparatus;
recording means for recording the signal from the signal processing means;
display means for displaying the signal from the signal processing means; and
a radiation source for generating the radiation.